Improved long-term biocompatibility of coronary stents by plasma coating process Abstract Drug-eluting stents (DES) have been widely used to treat patients of coronary heart disease (CHD) due to their better ability to control restenosis than bare metal stents (BMS). However, there is a high risk of late in-stent thrombosis associated with DES after implantation in patients, which could lead to fatal heart attack and death even though it occurs at low rate. Thus, for safe and effective clinical use, a coronary stent needs to have better long-term biocompatibility on its surface that will provide sufficient thrombo-resistance in addition to inhibiting smooth muscle cell proliferation thereby slowing down healing of tissues around the stent. Nanova, Inc. is developing a novel coating layer of high thrombo-resistance on the surface of stents made of stainless steel or CrCo. An environmentally benign technology, low temperature plasma process is used to deposit an ultra-thin (nano-scale) but continuous layer of coating, sufficient to generate desired abrasion resistance and immobilize the bioactive functional groups created in the subsequent surface treatment to prevent blood clotting and restenosis, but thin enough to allow for stent expansion without cracking when delivered into the atherosclerotic coronary arteries of patients. The knowledge gained in this innovative research project will also benefit research and development for improved biocompatibility for other implantable medical devices such as pacemakers, pulse generators, cardiac defibrillators and bio-sensors.